A strong pre-crisis performance by Maryland’s Euler Hermes, the largest trade accounts receivable insurer in the nation, earned it a “superior” financial strength rating from a ratings service.

Owings Mills, Md.-based Euler Hermes American Credit Indemnity Co. was issued a financial strength rating (FSR) of “A+” and an issuer credit rating of “aa-“ by credit rating organization A.M. Best, which said that despite “the negative impact of the credit crisis,” Euler Hermes ACI is expected to maintain this rating over the long term.

Effective risk management and risk reduction, strong capitalization and pre-crisis operating performance and the support provided by its group contributed to the stable rating, said A.M. Best in a statement.

The rating factored in the effects of the continued recession, A.M. Best said. Euler Hermes ACI saw a “noteworthy” drop in its risk-adjusted capitalization in 2009, in addition to high-frequency losses, adverse development and materially lower ceding commissions, according to the ratings service.